Twig: {% block %} and extend

I am trying to override a {% block %} in a file (index.html.twig) that extends the file where the block is used (base.html.twig). But the extending file is including another twig file (feature.twig) where the block that overrides the content in index.html.twig is placed.
Is that possible in any way? Maybe with something else than the include statement?